Development features

	Development features	Heartbeat	Mass
Week 1	Embryo, uterine wall, uterine cavity	No	0.5g
Week 4	Arm bud, eyes, umbilical cord, leg bud, embryo, amnion, placenta, uterine wall, uterine cavity	No	0.8g
Week 6	External ear, eyes, umbilical cord, amnion, placenta, uterine wall, uterine cavity, wrist region, fingers forming, head area, food plate	No	2g
Week 8	Ears, mouth, arms, legs, feet, amniotic fluid, uterine wall, eyes with eyelids, nose, fingers, hands, toes, placenta, umbilical cord, amnion.	No	15g
Week 12	Uterine wall, ears, mouth, arms, hands, amniotic fluid, legs, feet, amnion, eyes with eyelids, nose, fingers, placenta, umbilical cord, toes.	Yes	125g
Week 16	Skin is pink and transparent, ears, mouth, hands, arms, amniotic fluid, legs, uterine wall, eyes with eyelids, amnion, nose, fingers, placenta, umbilical cord, toes, feet.	Yes	350g
Week 28	Skin is red and wrinkled, legs, arms, mouth, nose, amniotic fluid, ears, body is covered with fine soft hair, uterine wall, feet toes, amnion, umbilical cord, hands, placenta, fingers, eyelashes, eyelids, eyebrows.	Yes	1500g
Week 36	legs, arms, mouth, nose, amniotic fluid, ears, downy covering has disappeared, fetus is in head down position, uterine wall, feet toes, amnion, umbilical cord, hands, placenta, fingers, eyelashes, eyelids, eyebrows.	Yes	3500g